Preliminary Icing Tests in the Climatic Chamber

Building a UAV Platform for Icing Condition Testing

The first winter season for conducting UAV icing tests under real-world conditions in the Steinalpl test area is approaching. To prepare for these field trials, a dedicated Uncrewed Aerial Vehicle (UAV) Flight Test Platform was designed and assembled over the past months. Based on a Holybro S500 V2 UAV kit, the platform integrates various sensors required for performance investigations, including current, temperature and humidity sensors, among others.

These sensor integrations enable both real-time system performance monitoring and environmental data acquisition during flight operations in icing conditions – key steps towards developing the Austrian Icing Map as part of the IFIRE project.

UAV - close up of underside - equipped with sensors and installed on test bed without propellers within the climatic chamber of FH JOANNEUM before the test run.

Pre- Tests in the climatic chamber

Prior to flight tests under natural icing conditions, it was essential to verify the flight capability and robustness of the UAV under controlled icing scenarios. Therefore, initial ground-based tests were conducted in the climatic chamber of FH JOANNEUM.
The test campaign pursued two main objectives:

Generation of Representative Artificial Ice Shapes:
The primary goal was to create realistic ice formations on the UAV’s propellers, which were subsequently 3D-scanned and 3D-printed. These artificially and accurately replicated ice geometries will later be used in dry-air tests to evaluate UAV performance and flight stability under simulated icing conditions.

Validation of Sensor Data Acquisition:

The secondary goal was to assess the sensor data and telemetry logging procedures, and to evaluate whether the mounting locations and performance of the humidity and temperature sensors on the UAV are suitable for future icing experiments.

Calibration and Test Setup

The climatic chamber setup included a spray rig provided by Pegasus, capable of generating controlled droplet distributions to simulate atmospheric icing conditions.

Prior to testing, FH JOANNEUM calibrated both the chamber and the spray rig. Liquid Water Content (LWC) measurements were performed using the rotating cylinder method to ensure representative and repeatable icing conditions.

UAV equipped with sensors and installed on test bed without propellers within the climatic chamber of FH JOANNEUM before the test run.

Climatic Chamber Test Campaign Reveals UAV Propeller Icing Effects and Performance Loss

Top view image of propeller after climate chamber test. Accumulated ice on the leading edge of the propeller.

After calibration, the UAV was mounted in the climatic chamber, and a total of seven test runs were completed at ambient temperature between –5 °C to –18 °C.

The tests confirmed a high susceptibility of UAV propellers to icing.
Within just 30 seconds of exposure to icing conditions at –5 °C, propeller thrust dropped by around 57 %. This rapid performance degradation clearly underlines the importance of further investigations into icing detection and mitigating strategies to ensure safe UAV operations in icing environments.

These results mark an important validation step for the IFIRE project, supporting its continued research on UAV icing performance and operational safety.

3D Scanning and Reconstruction of Iced UAV Propellers for Upcoming Flight Tests

Following the test campaign, detailed 3D scans of the iced propellers were performed to capture the exact geometry of the ice accretions. Based on these scans, artificially iced propellers will be reconstructed via 3D printing and installed on the UAV to conduct dry-air flight tests. These tests will serve to verify flight performance and controllability before carrying out full-scale icing tests in natural icing conditions during the upcoming winter season in Steinalpl test area.